CVE-2026-59809 json
SiYuan before v3.8.0 Secret Exfiltration via http_request URL
published 2026-08-22 2 mo ago modified 2026-10-12 27 d ago also EUVD-2026-64267
- cvss
- 4.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 35%
- public exploits
- 0
- none known
Summary
SiYuan before v3.8.0 interpolates secret placeholders into the destination URL parameter of the http_request MCP tool, allowing attackers to exfiltrate stored secrets. An MCP client can craft a request with an attacker-controlled URL containing secret placeholders to send plaintext secret values to any public host without confirmation.
Patch / fix
- siyuan-note siyuan 3.8.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 4.9 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N |
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- siyuan-note siyuan
Classification
- Weakness
-
- CWE-201 Insertion of Sensitive Information Into Sent Data
References
-
github.com
/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx
vendor-advisory
-
vulncheck.com
/advisories/siyuan-before-secret-exfiltration-via-http-request-url
third-party-advisory
Sources
- CVE List CVE-2026-59809
- NVD CVE-2026-59809
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